The study was conducted at the University of Auckland in New Zealand and was led by Dr. Ian Reid. The research team found that the cardiac risk increased even in those women who also took vitamin D. Vitamin D is a supplement that encourages â€œcalcium absorption and bone mineralization,â€ explained ABC News. A small stroke risk was also seen in this study, the team noted.

“When these results are taken together with the results of other clinical trials of calcium supplements, with or without vitamin D, they strongly suggest that calcium supplements modestly increase the risk of cardiovascular events, particularly myocardial infarction,” Reid and colleagues wrote in the report that was just published in the British Medical Journal (BMJ), quoted ABC News. “These data justify a reassessment of the use of calcium supplements in older people,” the team added.

Meanwhile, the data, which was derived from older studies, conflicts with prior WHI findings, said ABC News. “In other WHI analyses, we found no association between [calcium and vitamin D] supplementation and [coronary heart disease] or stroke death and neither did these authors,” said Andrea LaCroix, a professor of epidemiology at the Fred Hutchinson Cancer Research Center and a co-author of the earlier WHI studies, quoted ABC News.

Reid and his team say that cardiac risks were simply not noticed in prior studies because a large amount of the study participants were also taking calcium supplements that were not part of the study, wrote ABC News. The additional supplements were taken into consideration, said the researchers.

Another small study, also in New Zealand, indicated an increase in heart attack risk by 27-to-30 percent in women taking calcium without vitamin D, according to ABC News.

The LA Times said that the study measured, in women not taking additional calcium, for heart attack, coronary revascularization (a cardiac surgery), death from coronary heart disease, and stroke. Study authors conclude that more research is needed to understand if calcium is needed in the treatment of osteoporosis, added the LA Times.

Dr. Bart Clarke, an endocrinologist at the Mayo Clinic said that although the study does add to existing concerns over calcium use, it is not necessary to panic. â€œThe study is not conclusive proof, and there are limitations to the study pointed out in the article, but the implication is that calcium supplements may increase the risk of heart attack over time,â€ Clarke wrote in an email, quoted the LA Times.

According to Clarke, women should look for their calcium in foods such as dairy products and greens. â€œCalcium intake through the diet did not apparently add to the risk, so it may be safer to take calcium through the diet,â€ says Clarke.